The presently disclosed subject matter relates to a flow analyzer, a flow cytometer, and a flow analyzing method.
Flow cytometers are used when analyzing cells or the like. With a flow cytometer, sample liquid containing cells and particles is passed through a flow path called a flow cell, and the cells are analyzed by an image processing. When using a flow cytometer, it is important to accurately detect an abnormality in the flow path system (the location, width, and the like of a sample flow in the flow cell), and to correct the flow path system when there is an abnormality.
For example, JPH08-219975A discloses a particle image analyzer configured to detect an abnormality in an optical system or in a flow path system. The particle image analyzer irradiates an observation target region in a flow cell with light, and acquires a light intensity distribution of an image of particles (particle image) obtained through the irradiation to detect an abnormal state. JPH11-94727A discloses a flow-type particle image analyzer configured to irradiate a flow cell by a flash lamp like the analyzer of JPH08-219975A, and to analyze a particle image obtained by imaging the flow cell to analyze the sample flow. JP2002-062251A discloses a flow-type particle image analyzer configured to also irradiate a sample flow by a flash lamp to take a particle image, and to analyze the particle image to estimate a pattern of the sample flow.
In the related art described above, an abnormality in a flow path system is analyzed by using an imaging system that takes an image of a flow cell irradiated by a flash lamp. However, in a case where there is an abnormality in the imaging system, the flow path system cannot be assessed accurately. For example, it is possible that a distance between a camera and the flow cell or a position (in a depth direction and/or in a lateral direction) of an imaging location slightly changes due to a vibration or an unintended contact with the camera. When there is such an abnormality in the imaging system, a location through which particles pass in the flow cell cannot be detected accurately, and whether the sample flow passes through the center line of the flow cell cannot be evaluated accurately. The imaging system may be adjusted to address such issues (see, e.g., paragraph 0091 of JP2002-62251A), but such fine adjustment takes time and effort.
That is, the related art described above does not address a case where there is an abnormality (deviation) in an imaging system, in terms of accurately evaluating a sample flow.